The present invention relates to a valve having a valve housing, in the interior space of which is provided a fluid line piece whose outflow-side circumferential edge region forms a valve seat for a valve body, which valve body can be moved between an open position and a closed position by firstly the pressure, which acts on the valve body, of the fluid flowing in through the fluid line piece and secondly by a counterpressure, in which closed position the valve body acts on the outflow-side circumferential edge region of the fluid line piece.
For the operation of pressure-sensitive and in particular non-pressurized hot water generators, special outlet fittings are generally required which do not subject the water flowing through the supply line to an excessive resistance, and which thereby prevent an undesired pressure rise. For example, in conjunction with pressure-sensitive water generators, it is generally only possible to use non-aerated jet regulators, and therefore hot water outlets which do not generate a counterpressure.
Sanitary shower spray heads which have a spray head with a large spray surface area with a multiplicity of relatively small spray openings are becoming increasingly popular. With such shower spray heads it is possible to generate a shower jet pattern formed from a multiplicity of fine, thread-like individual jets. It is however disadvantageous that the spray openings, which have a relatively small clear cross section, can easily become blocked by limescale and dirt accumulations. As the spray openings become increasingly blocked, there is an increasing risk of the water flowing into the shower head causing a build-up of pressure which may lead to deformation and ultimately fracture of the spray head.
CH 46 886 A has previously described an actuating valve which is designed as an automatic pressure regulator and which has a valve housing, in the interior space of which is arranged a fluid line piece referred to as an inner housing. Whereas a pipe stub opens into the fluid line piece at the inflow side, the outflow-side circumferential edge region of the fluid line piece forms a valve seat for a plate-shaped valve body. The valve body is connected via a rod which leads coaxially through the fluid line piece to a first piston which is displaceably guided in the fluid line piece and to a second piston which seals off the valve housing. The second piston is acted on by a compression spring whose pressure can be varied by the adjustment of a threaded journal. The pressurized medium to be conducted through the already-known pressure regulator passes through said pipe stub into the fluid line piece, and from there through the valve seat into the valve housing. As a result, the second piston is pushed against the compression spring, wherein the valve moves more or less toward the closed position until the spring pressure and the medium pressure reach equilibrium. For as long as said equilibrium is maintained, the position of the valve also remains unchanged, such that the inflow of the medium into the valve housing is uniform. If the pressure of the entering medium is greater than the spring pressure, then the valve body moves toward the valve seat on the fluid line piece, possibly until the valve seat is completely closed, whereas in the reverse situation, the second piston is pushed by the compression spring against the fluid line piece referred to as an inner housing, and as a result the valve body is pushed away from the closed position at the valve seat. As a result of adjustment of the threaded journal, the compression spring can be compressed to a greater or lesser extent, and as a result the pressure of the medium emerging from the valve housing can be varied.